Race of male sex partners and occurrence of bacterial vaginosis

Longitudinal Profiling of the Macaque Vaginal Microbiome Reveals Similarities to Diverse Human Vaginal Communities

The vaginal microbiota plays an important role in women's reproductive and urogenital health. It is now well accepted that a "healthy" vaginal microbiome is dominated by Lactobacillus species. Disturbances in this microbial community can lead to several adverse outcomes, including pelvic inflammatory disease and bacterial vaginosis (BV), as well as increased susceptibility to sexually transmitted infections, miscarriage, and preterm births. However, vaginal communities, especially those of women in the developing world, can be comprised of a diverse set of microorganisms in the absence of overt clinical symptoms. The implications of these diverse vaginal microbiomes for women's health remain poorly understood. Rhesus macaques are an excellent translational animal model to address these questions due to significant physiological and genetic homology with humans. In this study, we performed a longitudinal analysis of clinical and microbiome data from 16 reproductive-age female rhesus macaques. At both the taxonomic and functional levels, the rhesus macaque vaginal microbiome was most similar to that of women who harbor a diverse vaginal community associated with asymptomatic/symptomatic bacterial vaginosis. Specifically, rhesus macaque vaginal microbiomes harbored a diverse set of anaerobic Gram-negative bacteria, including Sneathia, Prevotella, Porphyromonas, and Mobiluncus Interestingly, some animals were transiently colonized by Lactobacillus and some with Gardnerella Our in-depth and comprehensive analysis highlights the importance of the model to understand the health implications of a diverse vaginal microbiome and test interventions for manipulating this community.IMPORTANCE It is widely accepted that the "healthy" vaginal microbiome of women in the developed world is dominated by Lactobacillus species. However, in the developing world, many asymptomatic women harbor diverse vaginal microbial communities that are typically associated with bacterial vaginosis. Many questions remain about the drivers and health implications of a diverse vaginal microbial community. Rhesus macaques provide an excellent translational model to address these questions due to significant physiological and genetic homology with humans. In this study, we performed a longitudinal analysis of clinical and microbiome data from a large cohort of reproductive-age rhesus macaques. At the taxonomic, genomic, and functional levels, the rhesus macaque vaginal microbiome was most similar to that of humans, who harbor a diverse vaginal community associated with asymptomatic/symptomatic bacterial vaginosis. Our in-depth and comprehensive analysis highlights the utility of macaques as a model to study diverse vaginal community state types and test interventions for manipulating the vaginal microbiome.

Protection and Risk: Male and Female Genital Microbiota and Sexually Transmitted Infections

Unique compositional and functional features of the cervicovaginal microbiota have been associated with protection against and risk for sexually transmitted infections (STI). In men, our knowledge of the interaction between the penile microbiota and STI is less developed. The current state of our understanding of these microbiota and their role in select STIs is briefly reviewed, along with strategies that leverage existing findings to manipulate genital microbiota and optimize protection against STIs. Finally, we focus on major research gaps and present a framework for future studies.

Determinants of Vaginal Microbiota Composition

There is increasing evidence that the composition of a woman's vaginal microbiota significantly influences her sexual and reproductive health, including her risk of miscarriage, preterm birth, HIV and other sexually transmitted infections. Efforts to modulate the vaginal microbiota using antibiotic or probiotic therapy have shown limited lasting or reliable success. To explore the natural dynamics and causal pathways responsible for heterogeneity of vaginal microbiota composition we review the existing literature on its determinants, from the perspective of microorganism- and host-related factors. We then discuss how molecular approaches can be harnessed to advance our understanding of individual and population-level vaginal microbiota composition patterns. Work has been done to investigate determinants of microbial composition patterns in other body niches, but very little in the female genital tract so far. There is an urgent need to better understand vaginal microbiota composition patterns, across the lifespan, outside of the context of sexual health clinics, and in Sub-Saharan African women in whom vaginal microbiota composition may be a risk factor for HIV acquisition. More work is needed to clarify causal relationships between clinical symptoms, host genetic, host behavior, and molecular vaginal microbiota profiles. These insights will lay the groundwork for novel and targeted interventional approaches to improve women's sexual and reproductive health.

Differential sexual network connectivity offers a parsimonious explanation for population-level variations in the prevalence of bacterial vaginosis: a data-driven, model-supported hypothesis

BACKGROUND

The prevalence of bacterial vaginosis (BV) and vaginal microbiota types varies dramatically between different populations around the world. Understanding what underpins these differences is important, as high-diversity microbiotas associated with BV are implicated in adverse pregnancy outcomes and enhanced susceptibility to and transmission of sexually transmitted infections.

MAIN TEXT

We hypothesize that these variations in the vaginal microbiota can, in part, be explained by variations in the connectivity of sexual networks. We argue: 1) Couple-level data suggest that BV-associated bacteria can be sexually transmitted and hence high sexual network connectivity would be expected to promote the spread of BV-associated bacteria. Epidemiological studies have found positive associations between indicators of network connectivity and the prevalence of BV; 2) The relationship between BV prevalence and STI incidence/prevalence can be parsimoniously explained by differential network connectivity; 3) Studies from other mammals are generally supportive of the association between network connectivity and high-diversity vaginal microbiota.

CONCLUSION

To test this hypothesis, we propose a combination of empirical and simulation-based study designs.

Pathogenesis of Bacterial Vaginosis: Discussion of Current Hypotheses

In April 2015, the Division of Microbiology and Infectious Diseases of the National Institute of Allergy and Infectious Diseases hosted an experts technical consultation on bacterial vaginosis (BV), where data regarding controversies over the pathogenesis of BV were discussed. The discussion on the epidemiology and pathogenesis of BV is presented here, and several hypotheses on its pathogenesis are critiqued. Rigorous hypothesis-driven studies are needed to ultimately determine the cause of BV. This information is vital for the prevention and control of this important infection and its adverse public health consequences.

Association between bacterial vaginosis and partner concurrency: a longitudinal study

OBJECTIVES

The study aimed to test if there was an association between prevalent bacterial vaginosis (BV) and women reporting that their partner had other partners at the same time (partner concurrency). This association has not been assessed in a longitudinal cohort.

METHODS

The Longitudinal Study of Vaginal Flora recruited a cohort of 3620 non-pregnant women aged 15-44 years who presented for routine primary healthcare at 12 clinics in Birmingham, Alabama. Behavioural questionnaires and vaginal smears were obtained quarterly for a year and BV was defined by a Nugent score 7 or higher as well as Amsel criteria. Mixed effects logistic regression was used to assess the relationship between prevalent BV and reporting that one's partner had other partners in the preceding 3-6 months time interval.

RESULTS

Nugent score prevalent BV was associated with both reporting that one's partner definitely (adjusted OR (aOR) 1.5; 95% CI 1.2 to 1.8) and possibly (aOR 1.5; 95% CI 1.2 to 1.8) engaged in partner concurrency in the preceding 3-6 months time period. Prevalent BV diagnosed by Amsel criteria was similar.

CONCLUSIONS

A diagnosis of prevalent BV was associated with reporting that one's partner possibly or definitely engaged in partner concurrency.

"I just think that doctors need to ask more questions": Sexual minority and majority adolescents' experiences talking about sexuality with healthcare providers

OBJECTIVE

To examine adolescent and young adults' experiences of sexuality communication with physicians, and gain advice for improving interactions.

METHODS

Semi-structured interviews were conducted with questions focusing on: puberty, romantic attractions, sexual orientation, dating, sexual behavior, clinical environment, and role of parents. Interviews were transcribed and analyzed using thematic analysis with both open and axial coding.

RESULTS

Five themes emerged from interviews: 1) need for increased quantity of sexual communication, 2) issues of confidentiality/privacy, 3) comfort (physician discomfort, physical space), 4) inclusivity (language use, gender-fluid patients, office environment), 5) need for increased quality of sexual communication.

CONCLUSIONS

Sexual minority and majority adolescents and young adults indicate sexuality discussions with physicians are infrequent and need improvement. They indicate language use and clinical physical environment are important places where physicians can show inclusiveness and increase comfort.

PRACTICE IMPLICATIONS

Physicians should make an effort to include sexual communication at every visit. They should consider using indirect questions to assess sexual topics, provide other outlets for sexual health information, and ask parents to leave the exam room to improve confidentiality. Clinic staff should participate in Safe Zone trainings, and practices can promote inclusion with signs that indicate safe and accepting environments.

Bacterial Vaginosis Is Associated with Loss of Gamma Delta T Cells in the Female Reproductive Tract in Women in the Miami Women Interagency HIV Study (WIHS): A Cross Sectional Study

Bacterial vaginosis (BV) is the most common female reproductive tract infection and is associated with an increased risk of acquiring and transmitting HIV by a mechanism that is not well understood. Gamma delta (GD) T cells are essential components of the adaptive and innate immune system, are present in the female reproductive tract, and play an important role in epithelial barrier protection. GD1 cells predominate in the mucosal tissue and are important in maintaining mucosal integrity. GD2 cells predominate in peripheral blood and play a role in humoral immunity and in the immune response to pathogens. HIV infection is associated with changes in GD T cells frequencies in the periphery and in the female reproductive tract. The objective of this study is to evaluate if changes in vaginal flora occurring with BV are associated with changes in endocervical GD T cell responses, which could account for increased susceptibility to HIV. Seventeen HIV-infected (HIV+) and 17 HIV-uninfected (HIV-) pre-menopausal women underwent collection of vaginal swabs and endocervical cytobrushes. Vaginal flora was assessed using the Nugent score. GD T cells were assessed in cytobrush samples by flow cytometry. Median Nugent score was 5.0 and 41% of women had abnormal vaginal flora. In HIV uninfected women there was a negative correlation between Nugent score and cervical GD1 T cells (b for interaction = - 0.176, p<0.01); cervical GD1 T cells were higher in women with normal vaginal flora than in those with abnormal flora (45.00% vs 9.95%, p = 0.005); and cervical GD2 T cells were higher in women with abnormal flora than in those with normal flora (1.70% vs 0.35%, p = 0.023). GD T cells in the genital tract are protective (GD1) and are targets for HIV entry (GD2). The decrease in cervical GD1 and increase in GD2 T cells among women with abnormal vaginal flora predisposes women with BV to HIV acquisition. We propose to use GD T cell as markers of female genital tract vulnerability to HIV.

Evaluation of Health Disparity in Bacterial Vaginosis and the Implications for HIV-1 Acquisition in African American Women

There is a health disparity for both bacterial vaginosis (BV) and human immunodeficiency virus type 1 (HIV-1) infection in African American women that may be linked. The evidence that BV predisposes women to higher risk for HIV infection is well documented. The underlying mechanisms to support the epidemiological connections will require further investigations. This review explores the risk factors for BV disease with implications for HIV-1 acquisition in the context of race as a potential driver of the 20-fold increase in HIV-1 acquisition for African American women compared to white women. Specifically, it explores (i) disparities for BV in African American women, (ii) racial disparity for HIV-1 acquisition in African American women, (iii) common factors associated with BV and HIV acquisition in African American women, and (iv) potential mechanisms of the enhancement of HIV-1 transmission by BV.

A cross-sectional study of bacterial vaginosis, intravaginal practices and HIV genital shedding; implications for HIV transmission and women's health

OBJECTIVES

Bacterial vaginosis (BV) is associated with an increased risk of HIV transmission, and intravaginal practices (IVP) are an important risk factor for developing BV. The relationship between IVP, BV and HIV lower genital shedding, responsible for HIV transmission, has not been examined in women receiving antiretrovirals in Zambia.

DESIGN

Cross-sectional study.

SETTING

Community Health Center in Lusaka, Zambia.

PARTICIPANTS AND METHODS

Participants were HIV-infected women receiving antiretroviral therapy and engaging in IVP (n=128). Participants completed audio computer-administered self-interviews to assess IVP and underwent a vaginal examination. BV was diagnosed using Nugent criteria. HIV-1 lower genital shedding was assessed by measuring HIV-1 RNA in cervicovaginal lavages.

RESULTS

Most women engaged in IVP daily (114, 89.0%) and 81 (63.3%) of the participants had BV. HIV-1 genital shedding was detected in 18 (14.2%) participants. BV was associated with daily use of IVP (prevalence ratio, PR=4.58, CI 1.26 to 16.64, p=0.02) and weekly use of traditional medicines for IVP (PR=1.33, CI 1.05 to 1.68, p=0.02). The only factor associated with HIV-1 lower genital shedding was plasma viraemia (PR=4.61, CI 2.02 to 10.54, p<0.001). Neither IVP nor BV were associated with HIV shedding.

CONCLUSIONS

Despite the frequency of IVP and high prevalence of BV, plasma viraemia was the primary factor associated with HIV lower genital shedding. These findings support early initiation of antiretrovirals as an HIV prevention tool. Given adverse health outcomes associated with BV, the association between frequent IVP and BV, and the powerful local norms and traditions encouraging IVP, there is a need for studies assessing culturally tailored interventions to decrease BV in high-prevalence settings.

Strong association between the prevalence of bacterial vaginosis and male point-concurrency

OBJECTIVE

The prevalence of bacterial vaginosis (BV) differs considerably between different populations, and individual-level risk factors such as number of sex partners seem unable to explain these differences. The effect of network-level factors, such as the prevalence of partner concurrency (the proportion of sexual partnerships that overlap in time as opposed to running sequentially) on BV prevalence has not hitherto been investigated.

STUDY DESIGN

We performed linear regression to assess the relationship between the prevalence of male concurrency and prevalence of BV in each of 11 countries for which we could obtain comparable data. The data for concurrency prevalence were taken from the WHO/Global Programme on AIDS (GPA) sexual behavioural surveys. BV prevalence rates were obtained from a systematic review of the global patterning of BV.

RESULTS

We found a strong relationship between the prevalence of male concurrency and BV prevalence (Pearson's R(2)=0.57; P=0.007).

CONCLUSIONS

The findings of a strong ecological-level association between BV and partner concurrency need to be replicated and augmented with different types of studies such as multilevel prospective studies tracking the incidence of BV and associated individual, partner and network level risk factors.

Hormonal contraception is associated with a reduced risk of bacterial vaginosis: a systematic review and meta-analysis

Objective

To examine the association between hormonal contraception (HC) and bacterial vaginosis (BV) by systematic review and meta-analysis.

Methods

Medline, Web of Science and Embase databases were searched to 24/1/13 and duplicate references removed. Inclusion criteria 1) >20 BV cases; 2) accepted BV diagnostic method; 3) measure of HC-use either as combined oestrogen-progesterone HC (combined), progesterone-only contraception (POC) or unspecified HC (u-HC); 4) ≥10% of women using HC; 5) analysis of the association between BV and HC-use presented; 6) appropriate control group. Data extracted included: type of HC, BV diagnostic method and outcome (prevalent, incident, recurrent), and geographical and clinic-setting. Meta-analyses were conducted to calculate pooled effect sizes (ES), stratified by HC-type and BV outcome. This systematic review is registered with PROSPERO (CRD42013003699).

Results

Of 1713 unique references identified, 502 full-text articles were assessed for eligibility and 55 studies met inclusion criteria. Hormonal contraceptive use was associated with a significant reduction in the odds of prevalent BV (pooled effect size by random-effects [reES] = 0.68, 95%CI0.63–0.73), and in the relative risk (RR) of incident (reES = 0.82, 95%CI:0.72–0.92), and recurrent (reES = 0.69, 95%CI:0.59–0.91) BV. When stratified by HC-type, combined-HC and POC were both associated with decreased prevalence of BV and risk of incident BV. In the pooled analysis of the effect of HC-use on the composite outcome of prevalent/incident/recurrent BV, HC-use was associated with a reduced risk of any BV (reES = 0.78, 95%CI:0.74–0.82).

Conclusion

HC-use was associated with a significantly reduced risk of BV. This negative association was robust and present regardless of HC-type and evident across all three BV outcome measures. When stratified by HC-type, combined-HC and POC were both individually associated with a reduction in the prevalence and incidence of BV. This meta-analysis provides compelling evidence that HC-use influences a woman’s risk of BV, with important implications for clinicians and researchers in the field.

Vaginal infections update

Vaginal symptoms are one of the leading reasons that women visit their health care providers. Women often self-diagnose and may treat themselves inappropriately. This article describes the etiology, risk factors, symptoms, diagnosis, and treatment of the 3 most common vaginal infections: bacterial vaginosis, trichomoniasis, and vulvovaginal candidiasis.

Susceptibility of Gardnerella vaginalis biofilms to natural antimicrobials subtilosin, ε-poly-L-lysine, and lauramide arginine ethyl ester

Bacterial vaginosis is a common vaginal infection associated with numerous gynecological and obstetric complications. This condition is characterized by the presence of thick adherent vaginal biofilms, composed mainly of Gardnerella vaginalis. This organism is thought to be the primary aetiological cause of the infection paving the way for various opportunists to colonize the niche. Previously, we reported that the natural antimicrobials subtilosin, ε-poly-L-lysine, and lauramide arginine ethyl ester selectively inhibit the growth of this pathogen. In this study, we used plate counts to evaluate the efficacy of these antimicrobials against established biofilms of G. vaginalis. Additionally, we validated and compared two rapid methods (ATP viability and resazurin assays) for the assessment of cell viability in the antimicrobial-treated G. vaginalis biofilms. Out of the tested antimicrobials, lauramide arginine ethyl ester had the strongest bactericidal effect, followed by subtilosin, with clindamycin and polylysine showing the weakest effect. In comparison to plate counts, ATP viability and resazurin assays considerably underestimated the bactericidal effect of some antimicrobials. Our results indicate that these assays should be validated for every new application.